Modules: Convert SSL default option to Boolean in several modules

[bcoles]

A quick search through the library code reveals several instances (before I stopped looking) where using a string literal may result in unexpected behavior, as a value of 'False' or 'false' evaluates to true. I'm not sure if these code paths would be hit by the affected modules (because I didn't look); regardless, we should be consistent with other modules.

metasploit-framework/lib/msf/core/exploit/format/webarchive.rb

Line 331 in b6ed7f0

proto = (datastore["SSL"] ? "https" : "http")

metasploit-framework/lib/msf/core/exploit/remote/browser_autopwn2.rb

Line 554 in b6ed7f0

proto = (datastore['SSL'] ? "https" : "http")

metasploit-framework/lib/msf/core/exploit/remote/winrm.rb

Lines 62 to 63 in b6ed7f0

	ssl = datastore['SSL']
	schema = ssl ? 'https' : 'http'

irb(main):001> 'False' ? true : false
(irb):1: warning: string literal in condition
=> true

metasploit-framework/lib/msf/core/exploit/remote/http_server.rb

Lines 440 to 441 in b6ed7f0

	ssl = !!(datastore["SSL"])
	proto = (ssl ? "https://" : "http://")

irb(main):001> !!'False'
=> true